“In general, we have a tendency to notice positive stimuli in our environment,” said Fellowlvan Vargas, Ph.D, the lead scientist in this study. “We tend to focus on positive things more than anything else, but now we’re seeing that sleep deprivation may reverse that bias.”

What Happens When You Don’t Sleep For 28 Hours?

Dr. Fellowlvan Vargas studied what happened to 40 healthy adults when they had their sleep schedules altered. Some subjects stayed awake for 28 straight hours. Others had a full eight hours of sleep. Both groups took a test to measure their accuracy and response time to identify happy, sad and neutral faces.

The test results showed the sleep-deprived subjects focused less on the happy faces. Vargas noted the significance of these results, especially for people with depression or anxiety.

Depression is typically characterized as the tendency to think and feel more negatively or sad, but more than that, depression is associated with feeling less positive, less able to feel happy,” Vargas told Science Daily. “Similarly, if you don’t get enough sleep, it reduces your ability to attend to positive things, which over time may confer risk for depression.”

Lack Of Sleep A Growing Problem In U.S.

How much of a problem is sleep deprivation for the U.S.? Well, the Centers for Disease Control and Prevention identified lack of sleep as a “public health epidemic.” The CDC reports an estimated 50 to 70 million U.S. adults have a sleep or wakefulness disorder—for example, conditions such as snoring or obstructive sleep apnea.